HARARE, Zimbabwe (CNN) -- A power-sharing deal between Zimbabwean President Robert Mugabe and opposition leader Morgan Tsvangirai is just "one or two sticking points" away, sources close to the negotiations said Saturday.

South African President Thabo Mbeki was scheduled to arrive in Zimbabwe's capital, Harare, on Saturday to mediate another round of face-to-face talks between the two bitter political rivals, the sources said.

The sources did not elaborate on the nature of the issues still separating the sides.

The region has been engulfed in politically motivated violence since the disputed March presidential elections.